Suction box cover for a papermaking machine



Aug. 9, 1966 K. E. SAGER 3,265,560

SUCTION BOX COVER FOR A PAPERMAKING MACHINE Filed Jan. 20.. 1964 IB L 3' United States Patent 3,265,566 SUCTION BOX COVER FOR A PAPERMAKING MACI-HNE Karl E. Sager, Appleton, Wis, assignor to Kimberly- Clark Corporation, Neenah, Wis, a corporation of Delaware Filed Jan. 20, 1964, Ser. No. 338,972 3 Claims. (Cl. 162374) The invention relates to paperma-king machines of the Fourdrinier type and relates more particularly to improvements in suction boxes forming elements of such machines.

These suction boxes, of which several are usually employed, are located at the couch end of the machine and are spaced beneath the horizontal run of the Fourdrinier wire just before the latter reaches the couch roll. The suction boxes extend transversely across the machine and are provided with perforated or slotted covers. The boxes are connected with a suction pump or pumps which maintain a partial vacuum in the boxes; and, as the wire with its film of paper travels over the tops of the boxes, a portion of the water contained in the paper is sucked into the suction boxes. The partial vacuum within the boxes tends to hold the Wire against the covers of the boxes with considerable pressure, and as the wire is constantly moving transversely of the width of the boxes, it tends to wear grooves in the covers and is itself subjected to severe abrasion. This requires frequent resurfacing of the suction box covers and replacement of the costly Fourdinier wires.

The box covers have been made of various materials and perhaps wood is most customarily used. One of the chief objections to wood suction box covers is the amount of wear that occurs with such covers and the tendency for abrasive particles to embed themselves in the wood, causing accelerated Wear of the Fourdrinier wire. Therefore, harder materials for suction box covers have been proposed, such as synthetic resins, hard rubber, ceramic materials or metals. Stainless steel may be used, and preferably it is provided with a hard surface, such as with a layer of tungsten carbide, ceramic oxides, or welded overlays.

Many different patterns of openings have been used in suction box covers in the past. One of the most common includes round openings which are disposed in regular pattern across the width of the machine. Bars extending transversely of the machine and spaced longitudinally of the machine have also been used extensively. These bars provide elongated openings into a suction box which are equally spaced and are of equal width and extend transversely across the machine.

It is, in particular, the latter type of cover utilizing transversely extending bars with which my invention is concerned, and it is an object of the present invention to provide an improved suction box cover of this type utilizing a series of identical bars any one of which may be used to replace any one of the others. Since the bars are identical, spare bars may be kept in storage so that if there is breakage of, or undue wear on, any of the bars, the damaged bar may be easily replaced by any one of the spare bars in storage.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed .for carrying out the above stated objects, and such other objects, as will be apparent from the following description of a preferred form of the invention, illustrated with reference to the accompanying drawing, wherein:

FIG. 1 is a top plan view of a suction box having a cover embodying the principles of the invention; and

Patented August 9, 1966 FIG. 2 is a sectional View on an enlarged scale taken on line 22 of FIG. 1.

Like characters of reference designate like parts in the several views.

Referring now to the drawings, a suction box 10 is illustrated, which is adapted to be disposed beneath the screen wire of a Fourdrinier machine adjacent to the couch, as above mentioned. The suction box comprises a relatively narrow and shallow trough 11 preferablyformed of metal and provided with a flat upper edge surface 12 and a flange 13. A vacuum connection 14 is provided at one end of the box and is suitably connected to a source of vacuum for providing a partial vacuum within the suction box and for removing water which drains into the box. A rim 15 is disposed on the trough 11. The rim 15 has a flange 16 lying within the flang 13, and cap screws 17 extend through the flanges 13 and 16 for fastening the rim 15 on to the trough 11.

A plurality of support bars or struts 18 extend obbliquely across the trough 11 to opposite sides of the rim 15. The arrow A indicates the machine direction of the suction box and of the paper-making machine, that is, the direction in which the Fourdrinier wire passes over the suction box; and it will be noted from FIG. 1 that the support bars 18 extend approximately at an angle of 30 degrees with respect to the machine direction indicated by the arrow A. This angular disposition of the support bar is important in minimizing any tendency of the supporting structure to shadow-mark the freshly formed paper web. The bars, 18 are fixed in place with respect to the rim 15 by any suitable means, such as by welding.

The bars 18 are provided on their upper edges with equally spaced bosses 19, and Fourdrinier wire supporting bars 20 are disposed on top of the bosses 19 and extend from one end to the other end of the suction box. The rim 15 is provided with an upper flat surface 21 dispose-d at the same height as the tops of the bosses 19, and steel or ceramic bars 20 are also disposed on the surface 21, as will be noted.

Each of the bars 20 has a hard top surface 22 so as to provide long wearing capabilities. The top surface may be fiat, curved, beveled, placed at a slight angle or otherwise shaped for various water removal requirements. Each of the bars 20 is provided with a series of threaded blind openings 23 for receiving cap screws 24 that extend through the bars 18 and bosses 19 or through the rim 15 into the openings 2-3 for fixing the bars 20 with respect to the bars 18 and the rim 15. The bars 20 are all identical and the openings 23 are equally spaced and are identically located.

The rim 15 is provided with supporting end plate portions 25 on the ends of the suction box. The plate portions 25 are formed with slots 26 for receiving the bars 20, and it will be noted that the ends of the slots 26 lie on lines 27 that are parallel with the obliquely extending bars 18. The slots 26 define tongues 28 between them, and the tongues 28 are provided with holes 29 therethrough. The bars 20 terminate closely adjacent the ends of the slots 26, and the ends of the bars 20 lie on lines 30 that are adjacent the lines 27 and are parallel to the lines 27. It will be noted that the holes 29 lie on lines that extend diagonally with respect to the machine direction A.

The tongues 28 extend to lines 31 which lie in the machine direction, parallel with the arrow A. The paper web made on the Fourdrinier machine preferably has sufficient width so that its edges lie over the holes 29, the web having edges 32, and the Fourdrinier wire itself is of some width greater than that encompassed between the lines 32. It is contemplated that the paper web shall eventually be trimmed to have a width less than the distance between the ends of the tongues 28 such as along lines 33, in view of the fact that the holes 29 do not provide the same drying effect as do the slots between the parallel bars 20.

It will be observed that the end plate portions 25 and the rim 15 are integral and provide a frame for the suction box cover having a central opening B across. which the bars 20 extend. Since the suction box is much longer than wide, the minor axis of the frame and of the suction box is on a line parallel with the arrow A, and the support bars 18 and also the lines 27 and 30 extend diagonally with respect to the minor axis. The bars 20 extend longitudinally of the frame and of the suction box, and they are equally spaced. The tongues 28 terminate on the lines 31 that are parallel with the minor axis and with the machine direction A.

In operation, the Fourdrinier wire travels over the up per suction box surface provided by the bars 20, and suction is exerted on the paper web on the wire through the transverse slots between the bars 20. If, for any reason, it is desired to replace any one of the bars 20, it may be removed from the obliquely extending support bars 18 simply by removing the cap screws 24. All of the bars 20 are identical, in view of the fact that their ends lie equally distant and with only a small spacing from the line 27 defining the ends of the slots 26; and, therefore, a replacement bar 20 may be drawn from a stock of surplus bars 20. Since all of the bars 20 are identical, they need not be drilled and tapped just prior to assembly within the suction box to fit in a particular position and they need not be cut off to fit at one or both ends of the suction box. Any bar 20 can fit in any position in the suction box cover, and the predrilled and tapped holes 23 in the bars will line up With the corresponding holes for the screws 24 in the obliquely extending support bars 18 or in the rim 15.

Utilizing my improved suction box structure in which all of the cross bars 20 are identical, the risk of drilling and tapping these bars during assembly is avoided, and the costly alternatives of having a large stock of custom fit bars or of having overlength bars are also avoided.

I wish it to be understood that the invention is not to be limited to the specific constructions, arrangements, and devices shown and described, except only insofar as the claims may be so limited, as it will be understood to those skilled in the art that changes may be made without departing from the principles of the invention.

What is claimed is:

1. A suction box cover for use in contact With a moving screen of a Fourdrinier machine, said cover comprising a frame which is elongated in the direction of a major axis and having a central elongate opening therethrough with a plurality of equally spaced slots in the frame at the ends of the opening and defining tongues between the slots extending into the opening with the opening and slots and tongues all extending parallel with said major axis, a plurality of support struts fixed to said frame and extending between the sides of the frame and diagonally with respect to the minor axis of the frame which is at right angles to said major axis, said tongues terminating on lines parallel with said minor axis, a plurality of identical integral bars extending parallel with said major axis and into said slots at the opposite ends of said opening, and means for fixing said bars with respect to said support struts and thereby with respect to said frame.

2. A suction box cover for use in contact with a moving screen of a Fourdrinier machine, said cover comprising a frame which is elongated in the direction of a major axis and having a central elongate opening therethrough with a plurality of equally spaced slots in the frame at the ends of the opening and defining tongues between the slots extending into the opening with the opening and slots and tongues all extending parallel with said major axis, a plurality of support struts fixed to said frame and extending between the sides of the frame and diagonally with respect to the minor axis of the frame which is at right angles to said major axis, .said slots terminating on lines parallel with said support struts and said tongues terminating on lines parallel with said minor axis, a plurality of identical integral bars extending parallel with said major axis and into said slots at the opposite ends of said opening, and screws extending into said bars from said support struts for fixing the bars with respect to said support struts and thereby with respect to said frame.

3. A suction box cover for use in contact with a moving screen of a Fourdrinier machine, said cover comprising a frame which is elongated in the direction of a major axis and having a central elongate opening therethrough with a plurality of equally spaced slots in the frame at the ends of the opening and defining tongues between the slots extending into the opening with the opening and slots and tongues all extending parallel with said major axis, a plurality of support struts extending between the sides of said frame and diagonally with respect to the minor axis of the frame which is at right angles to said major axis, said slots terminating on lines parallel with said support struts and said tongues terminating on lines parallel with said minor axis, a plurality of identical integral bars extending parallel with said major axis and into said slots at the opposite ends of said opening, and screws extending into said bars from said support struts for fixing the bars with respect to said support struts and thereby with respect to said frame, said tongues being provided with spaced openings therethrough which lie on lines extending slightly diagonally with respect to said minor axis.

References Cited by the Examiner UNITED STATES PATENTS DONALL H. SYLVESTER, Primary Examiner.

I. H. NEWSOME, Assistant Examiner. 

1. A SUCTION BOX COVER FOR USE IN CONTACT WITH A MOVING SCREEN OF A FOURDRINIER MACHINE, SAID COVER COMPRISING A FRAME WHICH IS ELONGATED IN THE DIRECTION OF A MAJOR AXIS AND HAVING A CENTRAL ELONGATE OPENING THERETHROUGH WITH A PLURALITY OF EQUALLY SPACED SLOTS IN THE FRAME AT THE ENDS OF THE OPENING THE DEFINING TONGUES BETWEEN THE SLOTS EXTENDING INTO THE OPENING WITH THE OPENING AND SLOTS AND TONGUES ALL EXTENDING PARALLEL WITH SAID MAJOR AXIS, A PLURALITY OF SUPPORT STRUTS FIXED TO SAID FRAME AND EXTENDING BETWEEN THE SIDES OF THE FRAME AND DIAGONALLY WITH RESPECT TO THE MINOR AXIS OF THE FRAME WHICH IS AT RIGHT ANGLES TO SAID MAJOR AXIS, AND TONGUES TERMINATING ON LINES PARALLEL WITH SAID MINOR AXIS, A PLURALITY OF IDENTICAL INTEGRAL BARS EXTENDING PARALLEL WITH SAID MAJOR AXIS AND INTO SAID SLOTS AT THE OPPOSITE ENDS OF SAID OPENING, AND MEANS FOR FIXING SAID BARS WITH RESPECT TO SAID SUPPORT STRUTS AND WHEREBY WITH RESPECT TO SAID FRAME. 